HANNIBAL LECTER (1) WINNER

DARTH VADER (4)

If there was any Star Wars character in need of psychotherapy it would be Anakin Skywalker.  Mommy issues, daddy issues, inferiority complexes, obsessive behavior, night terrors, megalomania, depression, mental trauma, and so on.  All gravy for Dr. Lecter.  Anakin has also proven to be easily duped by the kinder older gentlemen hiding a dark secret.  They don't get much darker than Hannibal.  Not even Palpatine dined on his enemies.  

THE JOKER (2) WINNER

KHAN NOONIEN SINGH (3)

A man out for revenge is a scary thing.  A man out for chaos is even more frightening.  Khan's relentless linear thinking eventually makes him predictable.  There is no telling what depths or what ends The Joker would go to.  The Joker's intellect is also very comparable to Khan's.  The difference is Khan isn't certifiably insane.  A genius level intellect in the hands of a mad man is the personification of chaos.